Prediction of responsiveness to adjuvant anthracyclines in high-risk breast cancer patients

Abstract

597 Background: HER-2, TOP2A, and TIMP-1 have shown predictive properties regarding benefit from anthracyclines in patients with breast cancer. In the present study, TIMP-1 IHC was integrated with TOP2A FISH and HER-2 status in two separate profiles. Methods: The DBCG 89-D trial randomized 980 high-risk Danish breast cancer patients to nine series of CMF or CEF. CEF was superior to CMF in terms of DFS and OS (Ejlertsen et al, EJC 2007). HER-2 status and TOP2A copy number changes were determined as described previously (Knoop et al, J Clin Oncol. 2005). TMA s were constructed and analyzed centrally for TIMP-1 expression by IHC (± tumor cell immunoreactivity). TIMP-1 was combined with HER-2 into a joint HT marker (HT-non-responsive (HT-NR): HER-2 normal and TIMP-1 positive or HT-responsive (HT-R): HER-2 positive and/or TIMP-1 negative) and with TOP2A into a joint 2T marker (2T-NR: TOP2A normal and TIMP-1 positive or 2T-R: TOP2A abnormal and/or TIMP-1 negative). Relationships between IDFS, OS and the HT/2Tprofiles were analyzed using multivariate regression analysis. Results: Among patients with a HT-R profile CEF was superior to CMF in terms of both invasive disease-free survival (IDFS) (HR 0.62; 95% CI 0.45–0.86; p = 0.004) and overall survival (OS) (HR 0.63; 95% CI, 0.45–0.87; p = 0.005). In patients with a HT-NR profile, no significant differences between CEF and CMF were demonstrated for IDFS or OS. A significant HT profile (HT-R or HT-NR) versus treatment (CEF or CMF) interaction was detected by the Wald-test for both IDFS (p = 0.036) and OS (p = 0.047). An even more pronounced separation was observed regarding the 2T profile, and in patients with a 2T-R profile treatment with CEF was superior to CMF in terms of IDFS (HR 0.48; 95% CI 0.34–0.69; p < 0.001) and OS (HR 0.54; 95% CI, 0.38–0.77; p < 0.001). No significant difference was observed in patients with a 2T-NR profile. A highly significant 2T profile versus treatment interaction was detected for IDFS (p < 0.001) and OS (p = 0.004). Conclusions: Profiles created by joining TIMP-1 with either HER-2 status or TOP2A gene status seems advantageous compared to the use of a single marker. [Table: see text]